Field of the Invention
The invention relates to a device and method for generating an electrical discharge. In particular, the invention relates to the generation of an electrical charge within a chamber, such as a vacuum chamber for plasma treatment.
Description of Related Art
A plurality of devices and methods are known in which workpieces are treated within a vacuum chamber with an electrically generated plasma, for example in the form of plasma coating or plasma etching.
For example, DE 10 2006 021 994 A1 describes a coating method and a device for coating bodies by means of magnetron sputtering. Magnetrons are connected to a common anode in a PVD magnetron coating chamber. Substrates are guided along the magnetrons on a turntable. A magnetron can be operated in pulses or with constant power by means of two power supplies. Directly before being coated, the substrate is subjected to a plasma etching treatment in which a negative potential is applied to the substrate which is bombarded with argon ions to clean and activate the surface.
DE 10 2004 015 231 A1 describes a method and a device for treating substrate surfaces by bombarding with charge carriers. For surface treatment, a high-current gas discharge is formed between an electron emission device and an electrode connected as an anode. After evacuating a vacuum chamber, a hollow cathode installed in the wall of the chamber is activated with a heated tungsten tube, a cooled housing, an inlet device for the argon carrier gas, and an auxiliary electrode with a positive bias voltage which promotes the ignition and stabilization of a hollow cathode arc discharge.
DE 10 2004 015 230 A1 describes a method and a device for enhancing a pulsed magnetron discharge. An electrode is arranged in a magnetron magnetic field and temporarily operated to be a cathode relative to a counter-electrode. In time intervals in which the first electrode is not operated as a cathode, an additional electron current from an additional electron source is conducted to the first electrode. Hollow cathodes with a hot cathode as well as wire or bolt cathodes of tungsten, or respectively lanthanum hexaboride/tungsten are cited as the electron sources. In one embodiment, argon gas flows through a tubular hot cathode.
DE 100 60 002 A1 describes a device for surface treatment using a plasma generation chamber which is provided with a plasma generation electrode, and a substrate treatment chamber that is provided with a substrate support table. A plasma nozzle is used to as a generating area for a hollow anode discharge.
In the article by A. Sherman “In situ removal of native oxide from silicon wafers”, J. Vac. Sci. Technol. B. 8, 1990, 4, 656, 657, a water-cooled hollow cathode consisting of molybdenum as the electron source is used for a DC discharge for CVD deposition on silicon.